N_g_ben_vec = round(linspace(50,50,30)) ;

ret_aux_mat = zeros(N_g-1,30) ;

for tt=1:30
    for ii=1:N_g-1
        if ii>=N_g_ben_vec(tt)
            eval(['ret_aux_mat(', int2str(ii), ',', int2str(tt), ') = 1 ;']) 
        end
    end
end